Mexicans are sharing spectacular videos of bursts of blue lights seen streaking across the skies as a strong earthquake rocked the country's Pacific coast city of Acapulco on Wednesday.
The 7.0 magnitude quake struck some 11 miles northeast of the resort city in the southwestern state of Guerrero. At least one person was killed, buildings were damaged and rockslides littered a major highway, but the temblor didn't cause widespread damage. It did rattle nerves though.
The earthquake could be felt some 200 miles away in Mexico City and lasted nearly a minute. Residents fled into the streets as buildings swayed, sidewalks undulated and the blue lights burst brilliantly in the sky.
[...] Rutgers University physicist Troy Shinbrot says not to worry — the blue lights are not a sign of the world coming to an end. [...] In an interview with NPR, he said the phenomenon of so-called earthquake lights has been recorded historically and occurs fairly regularly.
Some scientists believe the eruption of light, or luminosity, is caused by the friction of rock near Earth's crust, which releases energy into the atmosphere. The flash of light is produced near the planet's surface.
Shinbrot has tried to re-create the phenomenon in his lab and says he has measured voltage changes similar to what happens when Earth's crust slips in an earthquake.
[...] There's disagreement about what actually causes the flashes. The U.S. Geological Survey makes that clear on its website, stating, "Geophysicists differ on the extent to which they think that individual reports of unusual lighting near the time and epicenter of an earthquake actually represent EQL."